An acoustic displacement flowmeter for determining flow rate of a fluid has a fluid flow line defining a flow path for the fluid. The fluid flow line has an inlet and an outlet. A controllable valve is positioned along the fluid flow line for opening and closing the flow path as desired, and an acoustic displacement transducer having a fluid port is coupled to the fluid flow line upstream from the controllable valve. The outlet of the fluid flow line extends through a wall isolating fluid exhausted from the outlet of the fluid flow line from electrical and/or mechanical components residing inside the flowmeter, thereby preventing the exhausted fluid, if explosive, from contacting such electrical and/or mechanical components which may act as potential ignition sources. Preferably, a manifold having a rigid body is provided in which the fluid flow line is formed. An acoustic displacement transducer (ADT) chamber wall is formed on the manifold body, and has an ADT chamber inlet port formed therein, and the fluid flow line has a branched portion connecting the fluid flow line to the ADT chamber inlet port. The outlet of the fluid flow line extends through a wall formed in the manifold body to isolate fluid exhausted from the outlet of the fluid flow line from electrical and/or mechanical components residing inside the flowmeter.